Low-profile platform scale

ABSTRACT

A low-profile platform scale has a base with a pair of upstanding portions at the central part of the front and rear margins of the base. Each upstanding portion, as a mounting post, has at an upper elevation a vertical flat surface facing one end of the scale and at a lower elevation a vertical flat surface facing the other end of the scale. The upper flat surfaces of the two upstanding portions are at one transverse vertical plane while the lower flat surfaces are at another transverse vertical plane. A lower primary U-shaped lever and an upper secondary Ushaped lever are pivotally mounted by flexure plates on these vertical surfaces of the upstanding portions of the base with the pairs of lever arms of the levers extending in opposite directions to the corner portions of the scale. The primary lever has an intermediate arm extending in the opposite direction to the pair of lever arms of that lever. The secondary lever has an extension in the opposite direction to its pair of lever arms and the extension is above the intermediate arm of the primary lever. That extension is connected by a flexible cable to the intermediate arm of the primary lever. The distal end portion of the intermediate arm is connected by a flexible cable to a load cell mounted on the base. The platform of the scale is spaced above the secondary lever and has at each of its corner portions a downwardly extended leg from which extends horizontally a foot. Two of the feet extend below the distal portions of the lever arms of the primary lever and the other two feet extend below the distal end portions of the lever arms of the secondary lever. These feet are connected to the pairs of lever arms of the two levers by flexible cables.

United States Patent [191 Czyryk LOW-PROFILE PLATFORM SCALE Chester S. Czyryk, Silver Lake, Wis.

[73] Assignee: Mangood Corporation, Chicago, Ill.

[22] Filed: Oct. 2, 1974 [21] Appl.No.: 511,426

[75] Inventor:

Primary ExaminerGeorge H. Miller, Jr. Attorney, Agent, or Firm-Claron N. White [57] ABSTRACT A low-profile platform scale has a base with a pair of upstanding portions at the central part of the front and rear margins of the base. Each upstanding portion, as a mounting post, has at an upper elevation a vertical flat surface facing one end of the scale and at a lower elevation a vertical flat surface facing the other end of 1 1 July 15, 1975 the scale. The upper flat surfaces of the two upstanding portions are at one transverse vertical plane while the lower flat surfaces are at another transverse vertical plane. A lower primary U-shaped lever and an upper secondary U-shaped lever are pivotally mounted by flexure plates on these vertical surfaces of the upstanding portions of the base with the pairs of lever arms of the levers extending in opposite directions to the corner portions of the scale. The primary lever has an intermediate arm extending in the oppo' site direction to the pair of lever arms of that lever. The secondary lever has an extension in the opposite direction to its pair of lever arms and the extension is above the intermediate am of the primary lever. That extension is connected by a flexible cable to the intermediate arm of the primary lever. The distal end portion of the intermediate arm is connected by a flexible cable to a load cell mounted on the base The platform of the scale is spaced above the secondary lever and has at each of its corner portions a downwardly extended leg from which extends horizontally a foot Two of the feet extend below the distal portions of the lever arms of the primary lever and the other two feet extend below the distal end portions of the lever arms of the secondary lever. These feet are connected to the pairs of lever arms of the two levers by flexible cables.

11 Claims, 16 Drawing Figures ill/Ill SHEET PATENTED JUL 1 5 ms LOW-PROFILE PLATFORM SCALE BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to a low-profile platform scale containing levers, flexure plates, flexible cables and a load cell.

2. Description of the Prior Art U.S. Pat. No. 3,658,143 describes and claims the most pertinent scale of the prior art. The abstract of the patent states that it is a patent for a platform scale having a simple lever system utilizing flexure plates and flexible cables to transmit forces from the platform to a hydraulic load cell to produce a hydraulic output signal having a pressure corresponding to the weight of an object placed on the platform."

The construction of the scale of that patent includes a base assembly having vertically extended posts at the four corners of the assembly. There are two levers. Each lever includes a pair of spaced generally horizontal lever arms extending from an intermediate portion of a torque-transmitting cylindrical member that extends between the front and back walls of the base assembly adjacent the side walls of the base assembly. The end portions of each of these torque-transmitting members are fixedly mounted on rectangular mounting blocks. On one vertical face of each block is mounted a fulcrum flexure plate. The fulcrum flexure plates are mounted on the vertically extended posts at the corners of the base assembly. The pairs of lever arms are offset from each other and their distal end portions are connected by flexure cables to the end portions of a transverse load-transfer bar that is above these arms and mounted on a centrally located load cell that is supported by the base assembly.

On the other vertical face of each of the mounting blocks on the end portions of the two torquetransmitting members of the levers is mounted the upper portion of a load flexure plate at a location generally diagonally opposite to the mounting of the fulcrum flexure plate on the block. The bottom portion of each of these load flexure plates is connected to a vertical flat side of end portions of a tubular rectangular member that is below each of the torque-transmitting members. The ends of the tubular members are connected by tie rods extending longitudinally adjacent to the front and side walls of the base. integral with and mounted on the end portions of the two rectangular tubular members are upstanding vertical posts having flat top ends which support the four corner portions of a platform.

In view of this construction of the platform scale of the patent mentioned above, it is seen that the weight on the platform provides a downward force on the four vertical posts mounted on the two tubular members connected by load flexure plates to the four mounting blocks that are supported by the fulcrum flexure plates mounted on upstanding posts of the base assembly. This force produces a downward movement of the ends of lever arms of the two levers thereby providing a downward force by the load-transfer bar to the load cell. This downward force on the load cell is measured to determine the weight on the platform.

lt is apparent that the scale of that patent uses the class of levers in which the force due to the weight to be measured is intermediate the fulcrum and the distal portion of the two levers at which the force is applied to a device to determine the weight on the platform.

SUMMARY OF THE INVENTION The low-profile platform scale has a construction containing a horizontal base, a platform, a pair of U- shaped levers, flexure plates, flexible cables or the like, and a load cell. As thus broadly stated it is similar to the platform scale of the patent mentioned above. However, there are many differences between the scale of that patent and the scale of the present invention.

One fundamental difference is the class of levers to which the two levers belong. In the scale of the present invention both levers are of a different class of lever than used in the scale of that patent. In the present construction each lever has a force applied to the distal portion of each of its pair of lever arms at corner portions of the scale by a weight on the platform. This force is applied to either lever by each pair of corners of the platform on one side of the fulcrum of the lever, while that force is applied by that lever at the opposite side of the fulcrum. This is the case, even though the force applied to the lever arms of the secondary lever by one pair of comer portions of the platform is applied by the upper secondary lever at its opposite side to the lower primary lever on the side of its fulcrum opposite the Side where force is applied to the pair of lever arms of the primary lever. The combined forces are applied by the primary lever to the load cell that is on the side of the fulcrum opposite to the side of the pair of arms of the secondary lever. The load cell is located adjacent that side of the base of the scale toward which the pair of lever arms of the secondary lever extends rather than being centrally located, as is the case of the scale of that patent. Another difference is the use of only four flexure plates in the scale of the present invention. Other differences will be apparent from the following description, including the detailed description of the drawings.

The horizontal base of the scale of the invention has two upstanding portions, as vertical mounting posts, located at the central part of the front and rear margin of the base. Each of these upstanding portions has at an upper vertical elevation a vertical flat wall surface portion facing one end of the base and at a lower elevation a vertical flat surface facing the other end of the scale. The upper flat surfaces of the two upstanding portions are at one transverse vertical plane while the lower flat surfaces are at another transverse vertical plane. The scale includes a primary U-shaped lever and a secondary U-shaped lever. Each lever, has in a unitary construction an elongated mounting member, that extends between the upstanding portions of the base, and a pair of lever arms spaced from each other and extending horizontally in the same direction that is normal to the longitudinal axis of the mounting member adjacent its end portions. The end portions of each of the mounting members of the U-shaped levers extend axially beyond the arms of each of these lever arms and have coplanar vertical flat sides. Flexure plates of the scale of the invention are secured to these two flat sides of each of the two levers and to the vertical flat wall surface portions of the upstanding portions of the base. The primary lever is thus mounted on and between the two upstanding portions of the base at a lower level by two flexure plates so that the two lever arms of the primary lever extend horizontally to a position above one end portion of the base. Similarly, the secondary lever is mounted on and between the upstanding portions of the base at an upper level by two flexure plates so that the two lever arms of the secondary lever extend to a position above the other end portion of the base.

The coplanar vertical flat sides of the end portions of the elongated member of each lever preferably face the same direction as the lever arms of that lever. That construction is preferred as the mounting of each flexure plate to an upstanding portion of the base and to one of the levers by screws is from the same side of the flexure plate and at that side of the plate there is greater accessibility to drive the screws into the end portions of the lever. In any event, each of the upstanding portions of the base has a recess directly below each of its vertical flat surfaces. In the preferred construction the end portions of the elongated members of the levers are located in these recesses for positioning their vertical faces for mounting on the flexure plates that are mounted on the upstanding portions of the base. Preferably these two recesses in each upstanding portion extend downwardly to the horizontal plane of the top of the main portion of the base.

The primary lever has in its unitary construction an intermediate arm extending from the elongated member in the horizontal direction, opposite to that of its pair of lever arms, to the other end portion of the scale. That intermediate arm is between and below the pair of lever arms of the secondary lever. The distal end portion of the intermediate arm of the primary lever is connected by a flexible cable or the like to the load cell mounted on the base at that end of the scale. The elongated member of the secondary lever has a intermediate extension located above the intermediate arm of the primary lever. A flexible cable or the like connects this extension to the intermediate arm of the primary lever at a position intermediate its ends.

The flexure plates are mounted on the flat surfaces of the upstanding portions of the base so that fulcrum axes of both levers are horizontal.

The construction of the scale of the invention is such that the fulcrum axis of the mounting of the secondary lever is at a transverse vertical plane passing through the intermediate arm of the primary lever and the intermediate extension of the secondary lever is connected to the primary lever between that vertical plane and the transverse vertical plane passing through the fulcrum axis of mounting of the primary lever.

The scale further includes a platform having at each of its corner portions a downwardly extending leg that supports a unitary horizontal foot. The legs extend downward sufficiently so that the feet are below the elevation of the pairs of lever arms of the two levers. The feet extend below and are spaced from their lever arms. Each of the feet is connected by a flexible cable or the like to the arm of the lever above it. Because the pair of lever arms of the primary lever are at a lower elevation than the pair of lever arms of the secondary lever, the legs at the corner portions at one end of the platform are longer than those at the other end in order to position the pairs of feet of the platform about the same distance below the pairs of lever arms so that flexible cables of the same length can be used for all four connections.

In view of the construction of thescale of the invention the addition of a weight on the platform provides a downward force from the feet of platform through the flexible cables to the distal end portions of the pairs of lever arms. This downward force on the pair of lever arms of the primary lever produces an upward force on the end of the intermediate arm. The downward force on the pair of arms of the secondary lever provides an upward force on its intermediate extension. That force is transmitted by the flexible cable to the intermediate arm of the primary lever. The combination of these two components of upward force is transmitted by the distal end portion of the intermediate arm of the primary lever to the load cell producing an analog signal in the load cell that can be converted to the digital value by one of a number of anaIog-to-digital conversion systems. Such conversion systems are well known in the art.

Although the upper and lower vertical flat surfaces of each upstanding portion of the base face in opposite directions in the preferred embodiment of the scale of the invention, a construction in which these surfaces face in the same direction is within the scope of the invention. Such construction has a stub extension toward the other upstanding portion and that stub extension is at one of the elevations and has the vertical flat surface having in the same direction as the vertical flat surface at the other elevation.

DESCRIPTION OF THE DRAWINGS FIG. I is a front elevation of the preferred embodiment of the platform scale of the present invention, with the platform cover sheet shown in section and without the adjustable feet mounted on the base of the scale to support it in a level manner for use.

FIG. 2 is a longitudinal section of the scale taken along the line 2-2 of FIG. 3.

FIG. 2a is a cross section, taken along the line 2a--2a of FIG. 2, of the intermediate arm of the primary lever showing the ferrule attaching that arm to the flexible cable that is attached to the load cell of the scale.

FIG. 3 is an end elevation of the scale as viewed from the line 33 of FIG. 1.

FIG. 4 is an elevation from the other end of the scale as viewed from the line 4-4 of FIG. 1.

FIG. 5 is a cross section taken along the line 55 of FIG. 1.

FIG. 6 is a top plan of the scale without the platform cover sheet and without the platform except for the bottom portion of its legs and the feet extending from those legs.

FIG. 7 is a fragmentary sectional view taken along line 77 of FIG. 6 and alongline 77 of FIG. 8 showing one of the flexure plate mountings of the secondary lever to one of the upstanding portions of the base.

FIG. 8 is a view taken along the line 88 of FIG. 7.

FIG. 9 is a bottom plan of a part of the platform of the scale.

FIG. 10 is a top plan of the secondary lever of the scale.

FIG. 11 is a top plan of the primary lever of the scale.

FIG. 12 is a top plan of the base of the scale.

FIG. 13 is a fragmentary longitudinal section of the scale to show the construction by which the secondary lever is connected below to the intermediate arm of the primary lever.

FIG. 14 is a fragmentary perspective view of the scale showing one of the flexure plate mountings of the secondary lever to one of the upstanding portions of the base.

FIG. is a fragmentary cross-section taken along the line 15-15 of FIG. 1 showing the ferrule in one of the lever arms of the primary lever, a foot and leg of the platform, and the ferrule and flexible cable connecting that lever arm to a foot of the platform.

DETAILED DESCRIPTION As seen in FIG. 1, the preferred embodiment of the scale generally indicated at 16 includes a base generally indicated at 17, a lower primary U-shaped lever generally indicated at 18, an upper secondary U-shaped lever generally indicated at 19, a platform generally indicated at 20, and a platform cover sheet 21.

The base 17 has a unitary grid construction including, as seen in FIG. 12, a front grid member 22, a rear grid member 23, end grid members 24 and 25, and transverse grid members 26 and 27 extending at the central transverse axis from grid members 22 and 23, respectively, to longitudinal grid members 28 and 29. The grid members 28 and 29 extend from grid member 24 on opposite sides of the longitudinal axis of the base to a transverse grid member 30 that is between the grid member 25 and grid members 26 and 27. The members 28 and 29 are joined at intermediate portions at their length by a number of grid members (not numbered). The grid member 30 is closer to grid member 25 than it is to grid members 26 and 27. At intermediate locations, closer to grid members 22 and 23 than are grid members 28 and 29, grid members (not numbered) connect grid members 25 and 30 leaving corner openings in the grid construction. Transverse grid members 31 and 32 join front and rear grid members 22 and 23, respectively, to longitudinal grid members 28 and 29, respectively. The grid members 31 and 32 are between end grid member 24 and grid members 26 and 27 and they are closer to end grid member 24 than they are to grid members 26 and 27 Openings at these corners remam.

The grid member 30 is located symmetrical with respect to grid members 31 and 32 that are located at the transverse plane at which a load cell 33 (FIG. 2) is supported by screws (not shown) in holes 34 in a plate 35 that is a unitary part of the construction of base 17 and that overlies grid members 28 and 29 from the top of grid member 24 to a location beyond grid members 31 and 32. Thus grid members 31 and 32 impart structural rigidity to the mounting of load cell 33 on support plate 35. The base 17 has as another part of its umitary construction a plate 36 over the intermediate portions of transverse grid member 30 and each grid member 25 that has at the mid part of its length an outward offset to provide an extension of that end of base 17 at which there is mounted on plate 36 a bubble-containing levelindicating devices 37 (FIG. 6) to indicate when adjustment of feet (not shown) mounted on base 17 provides scale 15 at the level position.

The unitary construction of base 17, in this preferred embodiment, is illustratively a cast article including plates 35 and 36 as well as the grid members mentioned above. The base 17 further includes a pair of upstanding, generally plate-shaped portions 40 and 41 that extend upwardly from the central portions of front and rear grid members 22 and 23. As seen in FIG. 1 for upstanding portion 40, each of upstanding portions 40 and 41 has at two different lateral extensions 42 and 43 and 44 and 45, respectively, that are parallel to front grid member 22 or rear member 23, respectively. The

lower extensions 42 and 44 face the end of base 17 having end grid member 25, while the upper extensions 43 and 45 face the end of base 17 containing end grid member 24. The four lateral extensions 42 through 45 have vertical flat surfaces 46, 47, 48 and 49, respectively, at vertical planes normal to the longitudinal axis of base 17. The upper flat surfaces 47 and 49 of upstanding portions 40 and 41 are at the same elevation and the lower flat surfaces 46 and 48 of upstanding portions 40 and 41 are at the same elevation. The lateral extensions 42 through 45 have top surfaces inclined to the top surface of the central part of upstanding portions 40 and 41. In this construction with the lateral extensions it is seen that both upstanding portions 40 and 41 provide an open space or recess between these lateral extensions and front grid member 22 or rear grid member 23. All of the lateral extensions have a construction that at the elevation of the flat surfaces are thicker to provide adequate width for mounting of lever 18 or lever 19 as described later. The front and rear vertical surfaces of the thickened portions are flat and parallel to the central longitudinal vertical plane of the base. These front surfaces for the thickened extensions of portion 40 are coplanar as are these rear surfaces of portion 41.

In the unitary construction of base 17 rigidity of upstanding portions 40 and 41 are insured by gussets 50 and 51, respectively, that are integral therewith and with grid members 26 and 27, respectively, from which they extend to the upstanding portions 40 and 41.

At about the location of grid members 30 and 31 front grid member 22 has forwardly extending bosses 52 and 53 (FIGS. 1, 6 and 12) in which are threaded vertical holes (not numbered). At the same transverse planes grid member 23 has rearwardly extending bosses 54 and 55 that also have vertical threaded holes (not numbered). In these holes of bosses 52 through 54 are mounted upstanding threaded rods of feet mentioned above. At the location of use of the scale these feet are adjusted in the holes until device 37 indicates that scale 16 is level on its support.

As seen in FIGS. 1, 6 and 12, front and rear grid members 22 and 23 also have centrally located, smaller forwardly extending and rearwardly extending bosses 56 and 57, respectively, with flat vertical surfaces that are coplanar with the vertical front and rear flat surfaces of the thickened portions of extensions 42 and 43,

and 44 and 45, respectively, of upstanding portions 40,

and 41. The bosses 56 and 57 and the adjacent portion of front and rear grid members 22 and 23 extend below the bottom surface of the main part of grid members 22 and 23 to provide downwardly facing bosses 58 and 59, respectively. The bosses 52 through 55 and an adjacent part of grid members 22 and 23 similarly extend below the bottom surface of the main part of rear grid member 23 to provide downwardly facing bosses 60 through 63. The bosses 58 through 63 are machined so that their downwardly facing surfaces are at the same horizontal plane. These bosses support base 17, without the feet, in a level condition on a level flat bed when the scale is assembled as described later.

Adjacent forwardly extending bosses 52 and 53, the front grid member 22 has on its upper surface bosses 64 and 65. The member 22 on its upper surface also has bosses 66 and 67 adjacent the transverse vertical planes passing through the vertical forwardly facing flat surfaces of extensions 42 and 43 of upstanding portion 40.

The rear grid member has similar upstanding bosses 68 through 71 on its top surface. The cast metal base 17 has bosses 64 through 71 machined to the same plane parallel to that of the surfaces of bosses 60-63.

The lower primary U-shaped lever 18 has in a unitary construction a pair of arms 72 and 73 that extend from the same side of an elongated member 74 adjacent its end portions 75 and 76, respectively. In this unitary construction lever 18 further includes an intermediate arm 77 that extends from the other side of elongated member 74 in a direction opposite to lever arms 72 and 73. As seen in FIG. 11, between the location of lever arm 72 and intermediate arm 77, member 74 has a number of upwardly facing elongated cavities (not numbered) and has similar cavities between arm 77 and lever arm 73. As seen, lever arms 72 and 73, and intermediate arm 77 also have upwardly facing elongated cavities and the cavity of each, that is at the proximal end of the arms, extends into member 74. These cavities reduce the weight of lever 18. Except for these cavities the top surface of arms 72, 73 and 77 and elongated member 74 have their top surfaces at a common horizontal plane. Above these coplanar surfaces are located a number of bosses that are machined to a common plane. Adjacent to elongated member 74 lever arms 72 and 73 have bosses 78 and 79, respectively, that are two of these bosses. Another is boss 80 on arm 73 adjacent its distal end. The fourth boss is boss 81 that is at the distal end portion of intermediate arm 77. These bosses are best seen in FIGS. 1, 2 and 11.

The bottom surfaces of lever arms 72 and 73 are inclined downwardly from their distal ends to their juncture with the bottom surface of elongated member 74 that is more steeply inclined toward its other bottom corner from which extends the bottom surface of arm 77, first in a flat horizontal manner and then inclined upwardly to its distal end.

The end portion 76 of elongated member 74, that extends beyond lever arm 73, has substantially less vertical height than that of the main portion of member 74. Furthermore, end portion 76 has parallel, flat horizontal top and bottom surfaces that are parallel to the machined top surfaces of bosses 78-81. The top surface of end portion 76 is slightly below the midpoint of the height of elongated member 74 from lever arm 72 to lever arm 73, so that the flexure axis of lever 18 is slightly above this top surface. The surface of the side of the end portion 76, that faces in the same direction as lever arm 73, is a flat vertical surface 82 that is normal to the longitudinal axes of arms 72, 73 and 77. The corners at the other junction of the bottom surface of end portion 76 and the other side of that end portion 76 is rounded. The end portion 75 is similarly constructed and has its vertical flat surface 83 coplanar with surface 82 of end portion 76.

The distal end portions of arms 72, 73 and 77 are provided with countersunk vertical holes (not numbered) and a pair of threaded horizontal holes, at 90 to each other, for placement of set screws to secure ferrules mounted in these countersunk holes as described later. The diameters of the countersunk hole in arm 73 are larger to receive an eccentric mounting for a ferrule, as seen below.

The upper secondary U-shaped lever 19 (FIG. has, also in a unitary construction, a pair of arms 84 and 85 extending horizontally in the same direction from an elongated member 85' adjacent its end portions 86 and 87, respectively. The lever 19 has cavities in its top surface in the same manner as lever 18. The lever 19 has a short intermediate extension instead of an intermediate arm like arm 77 of lever 18. This intermediate short extension comprises, on opposite sides of the mid point of the length of member a pair of vertical plate supports 88 and 89 that extend in the opposite direction to lever arms 84 and 85. At the location of plate supports 88 and 89, elongated member 85' has an offset portion from which they extend in a parallel manner normal to the longitudinal axis of elongated member 85. The opposed vertical flat surfaces of supports 88 and 89 are parallel to the longitudinal axes of lever arms 84 and 85. Adjacent their proximal ends supports 88 and 89 have vertical threaded holes (not numbered) extending from the top surface, for the purpose described later. It is seen that lever 19 has supports 88 and 89 instead of intermediate arm 77 of lever 18. The end portions 86 and 87 are constructed in the manner described above for end portions 75 and 76 of lever 18. Thus they have coplanar vertical surfaces 90 and 91 parallel to the longitudinal axis of member 85' and face in the same direction that arms 84 and 85 extend. The bottom surface of member 85' between end portions 86 and 87 is flat and horizontal. It is not required to be sharply inclined as in the case of lever 18 that has this inclination to provide an elongated one of the two threaded horizontal holes for introduction of a set screw as seen in FIG. 2 and described later. The bottom surfaces of arms 84 and 85 are inclined downwardly to the bottom surface of member 85' and the bottom surface of supports 88 and 89 are more sharply inclined downwardly from the distal ends to their juncture with the bottom surface of member 85'. The top surfaces of end portions 86 and 87 are, like the top surfaces of end portions 75 and 76 of lever 18, below the central horizontal plane of lever 19. The end surfaces of end portions 75 and 76 and 85 and 86 are flat, vertical and normal to the longitudinal axes of members 74 and 85'.

The lever 19 has its top surface at a horizontal plane except for a number of upstanding bosses that are machined to a common plane. Two of these are bosses 92 and 93 that are at the proximal portion of arms 84 and 85, respectively. The other boss is boss 94 that is adjacent the distal portion of arm 85 that has its horizontal top surface offset below the rest of arm 85, as has the distal portion of arm 73 beyond boss 80.

The distal end portions of lever arms 84 and 85 are provided with vertical countersunk holes (not numbered) for mounting of ferrules. On arm 85 the countersunk hole has larger diameters as does the hole in arm 73 of lever 18, for an eccentric mounting of a ferrule, described later. The distal portions of arms 84 and 85 also have a horizontal pair of threaded holes at right angles to each other to receive set screws to secure these ferrules in position.

The primary lever 18 is mounted on lateral extensions 42 and 44 of upright portions 40 and 41, respectively, by a pair of flexure plates 94 and secondary lever 19 is mounted on lateral extensions 43 and 45 of upright portions 40 and 41, respectively, by a pair of flexure plates 95 of the same construction as flexure plates 94. in the preferred embodiment, that is designed for weighing a load of up to 25 pounds, these flexure plates have a thickness of 0.006 inch and use spring steel. Each of these four flexure plates has four holes located in a rectangular pattern so that there are two holes on each side of and equally spaced from the center longitudinal line of the flexure plate. Each of the four holes is an equal distance from the central transverse line at which are located smaller holes having for each a center at a line that passes through the centers of two of the larger holes and parallel to the central longitudinal axis that is the flexure axis of primary lever 18 or secondary lever 19, as the case may be.

The vertical flat surfaces 46 through 49 of lateral extensions 42 through 45 of upright portions 40 and 41 and the vertical flat surfaces 82, 83, 90 and 91 of end portions 75 and 76 of lever 18 and of end portions 86 and 87 of lever 19 are each provided with a pair of horizontal threaded holes and between them a smaller hole, with the three holes being in horizontal alignment and spaced from one another in the same manner as either of the three holes on opposite sides of the central line of each of the flexure plates. The top portion of each of the two plates 94 are mounted in abutment with flat surfaces 46 and 48 of lateral extensions 42 and 44, while the bottom portion of each is mounted in abutment with flat surfaces 82 and 83 of end portions 76 and 75, respectively, of lever 18. The end portions 75 and 76 of lever 18 are spaced from and below lateral extensions 42 and 44. This mounting of flexure plates 94 is provided by screws 96 that pass through the larger holes in a pair of mounting clips 97 that abut the outer top portion of flexure plate 94 or the bottom portion of flexure plate 94 with the pair of mounting clips 97 spaced from the central line, i.e., flexure axis of the flexure plate 94. Thus there are four mounting clips for mounting lever 18. Each of these clips 97 has these two larger holes on either side of the center line of the flexure plate and has an intermediate smaller hole positioned as in the case of either smaller hole of either flexure plate 94 for mounting end portion 75 or 76 of lever 18. By this construction flexure plates 94 are securely mounted on lever 18 and on lateral extensions 42 and 44 of upright portions 40 and 41 of base 17 for pivotal mounting of lever 18 below and above the flexure lines of plates 94. These flexure lines are coaxial and horizontal.

The lever 19 is similarly mounted for pivotal movement by the pair of flexure plates 95 on lateral extensions 43 and 45 of upright portions 40 and 41 of base 17 using four mounting clips 97 and eight screws 96.

The two smaller holes in each of flexure plates 94 and 95, the smaller hole in each of mounting clips 97, and those in end portions 75 and 76 of lever 18 and in end portions 86 and 87 of lever 19, as well as those in the two lateral extensions each of end portions 40 and 41 are present for the placement of pins 98 used when assembling the components of scale 16 described below.

The platform 20 is a unitary construction and like base 17 has, in this preferred embodiment, a grid construction as seen in H6. 9. The platform 20 includes a front grid member 100 (FIG. 1), a rear grid member 101 and end grid members 102 and 103. The front and rear grid members 100 and 101 are rearwardly and forwardly offset, respectively, for their central portion, as seen in FIG. 9 for rear grid member 101. The facing surfaces of each of these ofi'set portions of grid members 100 and 101 are downwardly diverging, as seen in FIG. 9 for rear grid member 101. This construction provides clearance between grid members 100 and 101 and the top parts of upstanding portions 40 and 41 of base 17 when the components of the scale are assembled as described below, so as to minimize the height of the scale.

Between the offset portions of front and rear grid members and 101 extend transverse grid members 104 and 105. Between grid member 104 and end grid member 102 is a transverse grid member 106 and similarly between transverse grid member and end grid member 103 is a transverse grid member 107. On op posite sides of the central longitudinal axis are grid members (not numbered) connecting members 104 and 105, 104 and 106, and 105 and 107. Closer to rear grid member 101 than these unnumbered grid members are grid members 108 and 109 that connect end grid member 102 to transverse grid member 106 and end grid member 103 to transverse grid member 107, respectively. Similar to grid members 108 and 109 are grid members (not shown) that are closer to front grid member 100 than grid members (not shown), that are like grid members that connect transverse members 104-107 to one another, on the other side of the central longitudinal axis, as described above. At the central longitudinal axis there are grid members (not numbered) connecting end grid member 102 to member 106 and end member 103 to member 107.

In the unitary construction of platform 20 there are adjacent its four corners downwardly extending vertical plate-shaped legs 110, 111, 112 and 113 (best seen in FIGS. 1-4). The leg 112 extends downwardly from grid member 109 and end grid member 102. The leg 113 similarly extends from grid member 108 and end grid member 103. From the front portion of platform 20 extend legs and 111 from members corresponding to members 108 and 109 and end grid members 102 and 103, respectively. Vertical gussets 114 and 115 are connected to legs 112 and 113 and to grid members 102 and 103, respectively, to provide rigid positioning of these legs. Vertical gussets 116 and 117 (FIGS. 3 and 4) are connected to legs 110 and 111 and to end grid members 102 and 103, respectively, for their rigidity. At the bottom end of front legs 110 and 111 are forwardly extending horizontal feet 118 and 119, that has a vertical threaded hole (not numbered) for each at its distal portion. At the bottom end of rear legs 112 and 113 are rearwardly extending horizontal feet 120 and 121, that has a vertical threaded hole (not numbered) for each at its distal portion. Four smaller gussets (not numbered) are joined to the four legs and to the proximal portion of the feet to provide the rigid position of the feet.

On the corners of platform 20, on the mid portion of end grid members 102 and 103, on front and rear grid members 100 and 101 adjacent the recessed portions of these grid members, and on intermediate locations of transverse members 104 and 105, the top surface of platform 20 has a number of bosses that are machined to a common plane to provide a flat horizontal surface on which platform cover sheet 21 is placed during the completion of the assembly of scale 16.

Through the distal end portion of intermediate arm 77 of lever 18 there is a countersunk hole, as mentioned above. Mounted in this hole is one of five flexible cable ferrules 122, as seen in FIG. 2a. Each of ferrules 122 has an upper portion that rests in the countersunk portion of the hole while the lower portion, of smaller diameter, extends into the smaller diameter portion of the hole. The upper portion rests on the shoulder provided by the countersinking of the hole. The upper portion of ferrule 122 has a central annular recess at its outer surface that is engaged by screws 123 to prevent turning movement of ferrule 122 about its axis and to prevent its movement out of the countersunk hole. There is a small diameter hole passing through ferrule 122 at its longitudinal axis. For a part of the height of the upper portion of ferrule 122 there are two holes located in a diagonal to be engaged by a pair of pins of an adjusting tool during the assembly of scale 16. The other four ferrules 122 are similarly constructed. Each of ferrules 122 has the top end portion of a flexible cable 124 secured in its longitudinal hole.

Each oflever arm 72 of lever 18 and lever arm 84 has one of ferrules 122 mounted on their countersunk holes and secured by set screws. Secured in these ferrules 122 are the upper portion of two other flexible cables 124. In each of the larger countersunk holes in arms 73 and 85 of levers 18 and 19 are the other two ferrules 122. Each is mounted in an eccentric cylindrical mounting member 125 (shown in FIG. for lever arm 73 of lever 18). Each member 125 has an annular recess in the lower portion of its cylindrical surface to be engaged by a pair of set screws 126 and fix members 125 in the upper portion of the countersunk holes. The cylindrical mounting members 125 have eccentric vertical holes that are also countersunk with the larger diameter being at the top. In these eccentric holes of members 125 are mounted the two ferrules 122 for arms 73 and 85. These ferrules 122 are secured in members 125 by set screws 127. Flexible cables 124 have their upper end portions secured in ferrules 122 mounted in members 127 as in the case described above for ferrules 122 mounted on arms 72, 77 and 84. The top surface portion of each of members 125 has a pair of holes at a diagonal to be engaged by pins of another adjusting tool during the assembly of scale 16.

The secondary lever 19 is connected below to intermediate arm 77 of primary lever 18 in the following manner. A bracket 130 has a main portion between plate supports 88 and 89 on which rest uppermost lateral extensions 131 (P16. 4) of bracket 130 that are secured on supports 88 and 89 by screws 132 (FIG. 6) driven into the unnumbered vertical threaded holes in supports 88 and 89. The bracket 130 has a downward extension below the portion adjacent member 85 of lever 19. This extension of bracket 130 has a pair of horizontal holes through which pass screws 132' driven into member 85' of lever 19. The main portion of bracket 130 has at the central portion of its vertical surface, that faces in the direction that arm 77 extends, a recess with a configuration of one-half of a vertical countersunk hole. The other half of this countersunk hole is provided by a complementary facing surface of a central portion of a clamp member 133 so that when bracket 130 and member 133 are together they provide a countersunk vertical hole. The clamp member 133 is secured against that surface of bracket 130 by a pair of screws 134 extending horizontally into the upper portion of bracket 130 on opposite sides of its semicountersunk recess.

A cable hanger 135 has a pair of vertical holes mounted adjacent its margin closest to intermediate member 85' of lever 19. These holes are used to secure hanger 135 on bracket 130 by screws 136 that extend into vertical holes of top portion of bracket 130 generally between holes at which screws 132 mount bracket 130 to supports 88 and 89. The hanger 135 has a vertical hole above and in alignment with the countersunk hole provided by the assembly of bracket 130 and clamp member 133. A cable adjust bushing 137 having a hex-shaped upper portion of larger diameter than the hole in cable hanger 135 rests on hanger 135. The cylindrical bottom portion of bushing 137 is in the vertical hole in cable hanger 135 where it is secured by set screws 138 that are threaded through horizontal holes to engage an annular recess in the cylindrical surface of the bottom portion of bushing 137. A cable ferrule 139, that is a rod having a threaded upper portion that engages and extends upwardly through a central threaded hole (not numbered) in bushing 137. The bottom portion of ferrule 139 has a longitudinal hole in which is secured the top end portion of another flexible cable 124. The bottom end portion of this cable 124 is secured in the top cylindrical portion 140 of a ferrule 141 that has a cylindrical central portion of larger diameter and a bottom portion of an even larger diameter that fits in the countersunk part of a vertical hole 141 through intermediate arm 77 adjacent member 74 that has its bottom surface inclined downwardly in that direction. The central portion of ferrule 141 has an annular recess that is engaged by a screw (not shown) in the arm 77 from its side and by a screw 142 in the elongated horizontal hole extending through the bottom portion of member 74 from its inclined bottom surface.

This inclined surface of member 74 provides easier access for that set screw to secure ferrule 141 in arm 77.

The bottom portions of each of cables 124, mounted on arms 72, 73, 84 and 85, are secured in longitudinal holes drilled in ferrules 143. Each of ferrules 143 is a cylindrical rod with a bottom portion that is threaded. The threaded bottom portions of ferrules 143 are connected to feet 118 through 121 by engagement of ferrules 143 in the vertical threaded holes of these feet that are described above. By this construction each of the two lever arms of the two levers is connected to and supports one of the four feet of platform 20. A weight placed on platform cover sheet 21 and thus platform 20 provides a downward force on the four flexible cables 124 attached to these lever arms and thereby provides a downward movement of these arms of the levers. The downward movement of lever 19 provides an upward movement of supports 88 and 89 and thus an upward movement of flexible cable 124 connected by ferrule to lever arm 77. This produces an upward movement which combines with the upward movement of arm 77 created by the downward movement of arms 72 and 73. The end result is an upward force on flexible cable 124 at the end of arm 77. This flexible cable is connected by a ferrule 144 that is constructed like ferrules 143 and that has its lower end secured to a component of load cell 33. The upward movement of ferrule 144 produces a stress in the load cell that is illustratively a beam or column type of electronic load cell.

As mentioned earlier, all of lateral extensions 41 through 43'have at their distal ends a thicker construction to provide adequate width for mounting lever 18 and lever 19. These thickened portions have parallel front and rear vertical surfaces, as also mentioned. As seen in FIGS. 1, 6 and 14, this front vertical surface of extension 43 is surface 150. The corresponding coplanar front vertical surface 151 is on the thickened distal portion of extension 42. The surfaces and 151 are coplanar with front vertical surface 152 (FIGS. 1 and 6) of forwardly extending boss 56. The surface 152 was mentioned also earlier without a numbering assigned to this surface.

In this preferred embodiment of the scale of the invention lever arms 73 and 85 of levers l8 and 19 are provided with the eccentric mounting of ferrules 122 so that both eccentric mountings 125 are at the front side of the scale for the convenient access to eccentric members 125 for adjustment of the scale during its assembly.

Because of the basic construction of the scale of the present invention it is possible to construct a lowprofile platform scale having a small number of individual parts that are easy to assemble. This has the advantage of assembling the scale at low cost. Furthermore, because of the basic construction, it is possible to incorporate a number of structural features that permit the assembly of such scale with easy further adjustment, so that a weight placed on the platform is not required to be centrally located to provide a proper ascertainment of the weight. As a matter of fact the weight can be placed at any of the four corners of the platform and the scale will provide a proper indication of the weight of the article. This adjustment of the scale during its assembly, as described below, utilizes vertical flat surfaces of one of the upstanding portions, vertical flat surfaces of one end of each of the two levers, and horizontal flat upstanding bosses on the base, the two levers and the platform that are present in the construction of the preferred embodiment of the scale.

Because of the nature of the construction of scale 16, including the particular manner of flexure plate mounting of the two levers and the connection of the platform to it at its four corners, swaying or lateral movement of the platform is minimal and has no effect on the weighing operation. There are no check links etc. as required in the construction of the scale of US. Pat. No. 3,658,143.

In the preferred construction of the scale, the transverse vertical plane at which lever 19 is connected to intermediate arm 77 of lever 18 is at a location such that the downward force applied to arms 84 and 85 of lever 19, when equal to the downward force applied to arms 72 and 73 of lever 18, provides an upward force to arm 77 equal to the upward force provided at that location by the downward force on arms 72 and 73. For example, in an illustration of the preferred embodiment of the scale, lever arms 72 and 73 have the centers of their countersunk holes for ferrules 122 inches from the coplanar vertical plane of vertical surfaces 82 and 83 i.e., essentially the pivotal axis of lever 18. The countersunk hole at the end of arm 77 is 10 inches from that plane. The vertical transverse plane at which lever 18 is connected to lever 19 is two and one-half inches from the pivotal axis of lever 18. The lever 19 has the centers of its counterbore holes 5 inches from the plane containing its pivotal axis while the connection of the lever 19 to lever 18 is at a vertical axis that is 2% inches from that plane containing the pivotal axis of lever 19. For an equal downward force applied to arms 72, 73, 84 and 85, the upward force on arm 77 by lever 19 at the connection between the two levers equals the upward force provided by lever 19 to that location of its arm 77.

The preferred embodiment of the scale is assembled and adjusted in the following manner. The base 16 is placed on a support having a horizontal flat top surface with base 17 resting on its bosses 58 through 63. Two of pins 98 are placed in the smaller holes in the vertical flat surfaces 46 and 48 of lateral extensions 42 and 44 of upstanding portions 40 and 41, respectively, of base 17. The flexure plates 94 are placed on pins 98 using the top small hole of each flexure plate. Two of mounting clips 97 are placed on pins 98. Screws 96 are inserted through the larger holes of clips 97 and of flexure plates 94 and driven loosely into the corresponding holes in extensions 42 and 44.

The lever 19 is positioned above base 17 so that end portions 86 and 87 are below lateral extensions 42 and 44 and the vertical flat surfaces 82 and 83 of end portions 76 and abut the lower half of the two mounted flexure plates 94 from the same side as extensions 42 and 44 abut plates 94. Pins 98 are inserted through the small hole of each of two mounting clips 97 on the lower portion of flexure plates 94, through plates 94 and into the small holes at surfaces 83 and 82 of end portions 76 and 75. Then screws 96 are inserted through these clips 97 and plates 94 and loosely driven in end portions 76 and 75.

Using a ground plate as an assembly tool, lever 18 is swung laterally until the vertical flat surface at the end of end portion 76 and the vertical flat surfaces of 150, lSl, and 152 (FIG. 1) of extensions 43 and 42 of upstanding portion 40 and of boss 56 (FIG. 6) are all in contact with the ground plate. Then the eight screws 96 are tightened to securely mount lever 18 on base 17.

The load cell 33 is mounted on base 17 below its supporting plate 35 by screws extending through holes 34 into load cell 33. The screws are not tightened. A bolt (not shown) is screwed into a threaded hole (not shown) in arm 77 and the bottom end of the bolt abuts the support on which base 17 rests. The bolt is turned until arm 77 is reasonably horizontal. The bolt is retained in this position in arm 77 until a later time so that lever 18 is maintained in this position.

Using an appropriate tool, load cell 33 is shifted as necessary, until the location at which ferrule 144 is to be connected to cell 33 is aligned with the countersunk hole at the end portion of arm 77 of lever 18. Then the screws that mount cell 33 are tightened. An assembly of ferrule 122, flexible cable 124 and ferrule 144 is dropped into the countersunk hole at the end of arm 77 and rotated to move ferrule 144 in the threaded connecting part of cell 33 until ferrule 122 has its upper portion in the larger diameter part of the countersunk hole and cable 124 is taut, i.e., arm 77 can not be manually raised. Screws 123 are tightened in the annular recess of that upper portion to maintain ferrule 122 in arm 77.

The secondary lever 19 is mounted on upper lateral extensions 43 and 45 in the same manner as described above and screws 96 are not tightened until, using the ground plate, the lever has been swung so that the vertical flat surface at the end of end portion 87 and surfaces 150, 151 are all in contact with the ground plate.

The bracket 130 is mounted on plate supports 88 and 89 of lever 19 by screws 132 and to member by screws 132'. An assembly of ferrule 141, with its upstanding portion 140, flexible cable 124 and ferrule 129 is mounted on arm 77 with ferrule 141 in arm 77 and abutted loosely by two screws, including screw 142, holding it in position. The ferrule 139 is positioned adjacent bracket 130 and clamping member 133 is bolted into position onto bracket 130 by screws 134,

but they are not tightened so that cable 124 is not clamped at this time between bracket 130 and clamping member 133. The cable hanger 135 is mounted on bracket 130 with ferrule 139 extending through its main hole and hanger 135 is secured to bracket 130 by screws 136. The bushing 137 is rotated on ferrule 139 until bushing 137 abuts hanger 135 and lever 19 is reasonably horizontal. Then bushing 137 is secured against upward movement but not rotation by set screws 138.

Four cable assemblies are dropped into the countersunk holes at the end portions of lever arms 72, 73, 84 and 85 of levers 18 and 19. Each of these cable assemblies includes a fleixible cable 124 having its top end portion secured in one of cable ferrules 122 and having its bottom end portion secured in one of cable ferrules 143. The two cable assemblies that are dropped into arms 73 and 85 further include eccentric mounting members 125 in which ferriles 122 are mounted with set screws 127 preventing relative axial movement but not relative rotary movement. The screws 126 are tightened to prevent any movement of eccentric mountings 125 in arms 73 and 85. In the other two cable assemblies that are in arms 72 and 84, screws 123 are driven into the annular recesses of ferrules 122 but insufficiently to prevent their rotation.

The platform is lowered onto the foregoing assembly of base, levers etc. and moved laterally until the holes in feet 118 through 121 are directly below ferrules 143 of the four cable assemblies mounted on the four lever arms. The four cable assemblies are rotated to move ferrules 143 into feet 118-121 until platform 20 has been raised sufficiently for its grid members 100 and 101 to be spaced from upright portions 40 and 41 of base 17. The four cable assemblies are rotated until raised platform 20 is horizontal as determined by the top surface of its upwardly facing bosses being level. Of course, platform 20 is raised sufficiently from uprights 40 and 41 when the maximum weight, for which the scale is designed, is on the scale.

The scale 16, assembled in the manner described above, is adjusted as follows. The top surfaces of bosses 79 and 81 of lever 18 are made parallel to the top surfaces of bosses 64 through 71, as determined by a depth micrometer, by rotating the cable assembly at the end of arm 77. Then lever 19 is made horizontal so that the top surfaces of its bosses 93 and 94 are parallel to the top surfaces of bosses 64 through 71 of base 17, as determined in the same manner as for lever 18, by rotating bushing 137. A known weight is placed on the rear corner of platform 20 above the distal portion of arm 72. The electronic readout of the stress created in load cell 33 by the application of this known weight should display approximately the correct weight. The same weight is then placed on the other rear corner portion of platform 20, i.e., above the distal portion of arm 84. The electronic readout should be approximately the same as that displayed when the weight was on the rear corner portion above arm 72. If it is not, a second adjustment is made at the interconnection between the primary and secondary levers shown in FIG. 13. To do this, screws 132 are loosened and then screws 132' are turned in one direction or the other until the weight displayed is sufficiently close to the weight displayed for the first rear corner. Then screw's 132 are tightened.

The known weight is placed on each of the front corners of scale 16 for a readout display. If the weight on a front corner does not provide essentially the same display obtained by readout of the weight at the two rear corners, screws 126 in the lever arm at that front corner are loosened. The eccentric mounting member is rotated to increase or decrease the displayed weight. The screws 126 are then tightened.

The platform cover sheet 21 is now placed on platform 20.

In view of the grid construction of base 17 that provides relatively large open spaces at the four corner portions and at the central zone, the preferred construction provides clearance and access below the feet of platform 20 and below the cable assembly connecting the two levers with a minimum height of the upstanding portions of the base and thus provide a low profile for the scale. Also, two of the open corner portions permit the feet of the platform, that are connected to the primary lever, to be below the top elevation of the base for a further attainment of a low profile.

The foregoing description has been presented solely for the purpose of illustration and not by way of limitation of the invention because the latter is limited only by the claims that follow.

I CLAIM:

1. A platform scale comprising:

a horizontal base;

a primary U-shaped lever having in a unitary construction an elongated mounting member, a pair of lever arms extending horizontally from the same side of said mounting member adjacent its ends, and an intermediate arm extending horizontally from said mounting member in a direction that is normal to the longitudinal axis of said mounting member and from the side of said mounting member that is opposite to the side from which said pair of lever arms extend;

a secondary U-shaped lever having in a unitary construction an elongated mounting member and a pair of lever arms extending horizontally from the same side of said mounting member adjacent its ends, said mounting member having an intermediate portion extending horizontally and normal to the longitudinal axis from the side of said mounting member that is opposite to the side from which said pair of lever arms of said secondary lever extend;

means connected to said base and to said mounting member of said primary lever to pivotally mount that mounting member at a horizontal axis that is at a lower elevation above the central transverse portion of said base, with the longitudinal axis of that mounting member at a vertical plane transverse to the longitudinal axis of said base and with the distal end portions of said pair of lever arms of said primary lever above the front and rear corner portions of one end of said base;

means connected to said base and to said mounting member of said secondary lever to pivotally mount that mounting member at a horizontal axis that is at an upper elevation above the central transverse portion of said base, with the longitudinal axis of that mounting member at a vertical plane transverse to the longitudinal axis of said base and passing through said intermediate arm of said primary lever, with the said extension of said intermediate portion of said mounting member of said secondary lever directly above said intermediate arm of said primary lever, and with the distal end portions of said pair of lever arms of said secondary lever above the front and rear corner portions of the other end of said base;

a horizontal platform;

force-transmitting support means connected to the corner portions of said platform and to the distal end portions of said pairs of lever arms of said levers to support said platform above said lever arms;

force-transmitting means connected to said intermediate extension of said mounting arm of said secondary lever and to said intermediate arm of said primary lever;

low cell means mounted on said base adjacent that its said other end and below the distal end portion of said intermediate arm of said primary lever; and

force-transmitting means connected to said distal end portion of said intermediate arm and to said load cell means to provide a stress in said load cell means when said intermediate arm is raised.

2. A platform scale comprising:

a horizontal base having front and rear upstanding portions at the central part of the front and rear margins of said base, each upstanding portion providing a vertical mounting post having at an upper elevation a vertical flat surface facing one end of said scale and at a lower elevation a vertical flat surface facing one end of said scale, said upper flat surfaces of said upstanding portions being at one vertical plane transverse to the longitudinal axis of said base and said lower flat surfaces being at another vertical plane transverse to the longitudinal axis of said base;

a primary U-shaped lever having in a unitary construction an elongated mounting member, a pair of lever arms spaced from each other and extending horizontally from the same side of said mounting member adjacent its end portions, and an intermediate arm extending horizontally from said mounting member in a direction that is normal to the longitudinal axis of said mounting member and from the side of said mounting member that is opposite to the side from which said pair of lever arms extend, side end portions of said mounting member extending axially beyond said pair of lever arms and having coplanar vertical flat surface portions on the same side of the longitudinal axis of said mounting member;

a secondary U-shaped lever having in a unitary construction an elongated mounting member and a pair of lever arms spaced from each other and extending horizontally from the same side of said mounting member adjacent its end portions, said mounting member having an intermediate portion extending horizontally and normal to the longitudinal axis of said mounting member from the side of said mounting member that is opposite to the side from which said pair of lever arms of said secondary lever extend and said end portions of said mounting member extending axially beyond said pair of lever arms and having coplanr vertical flat surface portions on the same side of the longitudinal axis of said mounting member;

means, including a first pair of flexure plates, pivotally mounting said primary lever on said upstanding portions of said base with said pair of lever arms of said primary lever extending to positions above front and rear corner portions of one end of said base, said mounting means connecting said primary lever at its said coplanar vertical flat surface portions to one of the upper and lower horizontal marginal portions of said first pair of flexure plates and connecting said upstanding portions at their said lower vertical flat surfaces to said first pair of flex ure plates at the other of said upper and lower marginal portions of said first pair of flexure plates to provide a common horizontal flexure axis transverse to the longitudinal axis of said base and to provide the end portions of said mounting member of said primary lever vertically spaced from said upstanding portions at their said lower vertical flat surfaces;

means, including a second pair of flexure plates, pivotally mounting said secondary lever on said first and second upstanding portions of said base with said pair of lever arms of said secondary lever extending to positions above front and rear corner portions of the other end of said base, said mounting means connecting said secondary lever at its said coplanar vertical flat surface portions to one of the upper and lower horizontal marginal portions of said second pair of flexure plates and connecting said first and second upstanding portions at their said upper vertical flat surfaces to said second pair of flexure plates at the other of said upper and lower marginal portions of said second pair of flexure plates to provide a common horizontal flexure axis transverse to the longitudinal axis of said base and to provide the end portions of said mounting member of said secondary lever vertically spaced from said upstanding portions at their said upper vertical flat surfaces;

a platform having a main horizontal portion, with the longitudinal axis parallel to the longitudinal axis of said base and with corner portions above the corner portions of said base, a first pair of downwardly extending legs at the front and rear corner portions of one end of the main portion of said platform below which are located the front and rear corner portions of said one end of said base, a first pair of horizontal feet extending from said first pair of legs to a position below the distal end portions of said lever arms of said primary lever, a second pair of downwardly extending shorter legs at the front and rear comer portions at the other end of the main portion of said platform below which are located the front and rear corner portions of said other end of said base, a second pair of horizontal feet extending from said second pair of legs to a position below the distal end portions of said lever arms of said secondary lever;

means connected to the distal end portions of said lever arms of said primary lever and to said first pair of feet to provide a part of the support of said platform by said lever arms;

means connected to the distal end portions of said lever arms of said secondary lever and to said second pair of feet to provide the other part of the support of said platform by said lever arms;

means connected to said intermediate extension of said mounting member of said secondary lever and to said intermediate arm of said primary lever at a location spaced from the distal end portion of said intermediate arm and spaced from said mounting member of said primary lever, said intermediate extension of said mounting member of said secondary lever and said intermediate arm of said primary lever being located on said levers so that said extension is directly above said intermediate arm;

load cell means mounted on said base adjacent its said other end and below the distal end portion of said intermediate arm of said primary lever; and

means connected to said distal end portion of said intermediate arm and to said load cell means to provide a stress in said load cell means when said intermediate arm is raised.

3. The scale of claim 2 wherein:

said pairs of lever arms of said levers extend normal to the longitudinal axes of the corresponding mounting member of said levers and each lever arm of said primary lever has its longitudinal axis in alignment with that of one of said lever arms of said secondary lever;

each of said distal end portions of said pairs of lever arms has a vertical countersunk hole at the longitudinal axis of that lever arm and horizontal threaded holes to the larger diameter portion of the counter sunk hole;

each of said pairs of feet has a threaded vertical hole located below said countersunk hole in the distal end portion of the lever arm connected to that foot;

said means connecting said distal end portions of said lever arms of said primary lever to said first pair of feet and said means connecting said distal end portions of said lever arms of said secondary lever to said second pair of feet comprises: four flexible cable assemblies, each assembly including:

a vertical flexible cable;

a ferrule rod having a threaded cylindrical bottom portion threaded into said hole in one of said feet and an upper portion with a central vertical hole in which the bottom end portion of said flexible cable is secured; and

a ferrule with a stepped cylindrical surface mounted on one of said lever arms in the countersunk hole and having a central vertical hole, in which one end portion of said flexible cable is secured in the portion of smaller diameter and having an intermediate annular recess in the cylindrical surface of larger diameter portion; and

screws mounted in said horizontal threaded holes in said distal end portion of the lever arm and engaging said stepped ferrule at its said intermediate annular recess; and

said intermediate arm of said primary lever having an inverted countersunk hole below said intermediate extension of said mounting member of said secondary lever and horizontal threaded holes to the large diameter portion of that countersunk hole; said means connecting said intermediate extension and said intermediate arm of said primary lever comprising: another of said flexible cable assemblies in an inverted position with said stepped ferrule being mounted in said inverted countersunk hole of said intermediate arm and with the ferrule rod at the elevation of said extension of said mounting member of said secondary lever;

screws mounted in said horizontal threaded hole in said intermediate arm and engaging said stepped ferrule at its said intermediate annular recess; and

means mounted on that intermediate extension of said secondary lever and fixedly engaging that ferrule rod;

said intermediate arm of said primary lever has at its distal portion a vertical countersunk hole and horizontal threaded holes to the larger diameter of that countersunk hole; and

said means connecting said distal end portion of said intermediate arm comprises:

another of said flexible cable assemblies having its ferrule rod threadedly engaging said load cell means and having its stepped ferrule in said countersunk hole; and

screws mounted in said horizontal threaded holes in said distal end portion of said intermediate arm and engaging said stepped ferrule at its said intermediate annular recess.

4. The scale of claim 3 wherein: said intermediate extension of said mounting member of said secondary lever comprises a pair of spaced plate extensions having parallel facing surfaces and coplanar horizontal flat top surface portions;

said means fixedly engaging said ferrule rod of said cable assembly connecting said intermediate arm of said primary lever and said extension of said secondary lever comprises:

a bracket having at its upper portion lateral extensions fixedly mounted on said coplanar flat top surface portions of said plate extensions and having at its vertical surface facing away from said secondary lever a central recess conforming to one-half of a countersunk hole;

a cable clamp member having at its upper portion lateral extensions mounted on said top surface portions of said plate extensions, having a vertical surface that faces said recessed surface of said bracket and that is flat except for a complementary recess that provides the balance of a countersunk hole when said bracket and said clamp rhemberare secured together, the bottom portion of the countersunk hole thus provided having a smaller diameter than the flexible cable to secure said cable between said bracket and said clamp;

screws securely mountingsaid clamp member on said bracket;

a cable hanger mounted on said bracket and said clamp member, said hanger having a vertical hole in alignment with the countersunk hole provided by said bracket and said clamp member and having horizontal threaded holes to said vertical hole;

screws securing said hanger on said bracket;

a bushing having a threaded vertical central hole, a lower portion with a cylindrical configuration and an intermediate annular recess, and an upper portion of larger diameter resting on said hanger, said lower portion of said bushing mounted in said vertical hole of said hanger and the threaded end portion of said ferrule rod of said cable assembly connected to said intermediate arm in said threaded vertical hole of said bushing; and

screws in said horizontal holes in said cable hanger securing said bushing by engaging said annular recess of said bushing.

5. The scale of claim 4 wherein said mounting for one of said cable assemblies on the distal portions of said lever arms of said primary lever and for one of said cable assemblies on the distal end portions of said lever arms of said secondary lever is provided for each by:

a cylindrical mounting member having:

an annular recess in its bottom surface portion;

an eccentric vertical countersunk hole in which is located the stepped ferrule of the cable assembly with the larger diameter portion of the ferrule in the countersunk portion of the hole in said cylindrical mounting member; and

horizontal threaded holes in its upper portion to said countersunk hole; and

screws in said threaded holes engaging the annular recess in the stepped ferrule,

said screws in said lever arm engaging the annular recess in said cylindrical eccentric mounting member.

6. The scale of claim 5 wherein said eccentric mounting members in the countersunk holes of said lever arms are in the lever arms that are adjacent the front of said base.

7. The scale of claim 6 wherein:

said lower flat surfaces of said upstanding portions of said base face in the direction that said lever arms of said primary lever extend;

said upper flat surfaces of said upstanding portions of said base face in the direction that said arms of said secondary lever extend;

said coplanar vertical flat surface portions of said end portions of said mounting member of said primary lever face in the direction that said lever arms of that lever extend; and

said coplanar vertical flat surface portions of said end portions of said mounting member of said secondary lever face in the direction that said lever arms of that lever extend.

8. The scale of claim 3 wherein:

said horizontal base having in a unitary construction:

a main horizontal portion with a grid construction comprising: front and rear grid members; first and second end grid members constituting said one and said other ends of said base; and transverse and longitudinal gridmembers within the area defined by said front and rear and said end members to provide with them the grid construction having open spaces at the four corner portions of said main horizontal portion and having a central open space from which two of said transverse grid members extend to the front and rear grid members at the central vertical plane of said horizontal main portion; front and rear vertical plates extending upwardly from the central portion of said front and rear grid members, respectively, and constituting said upstanding portions of said base, each of said vertical plates having a lower lateral extension, toward the transverse vertical plane containing said first end grid member, and an upper lateral extension, toward the transverse vertical plane containing said second end grid member, with the distal end portions of said upper and lower lateral extensions of said plates being thickened to provide sufficient horizontal width at the end surface for mounting of said pairs of flexure plates on said four lateral extensions, and with the end surfaces of these thickened portions of said lateral extensions being vertical and flat to provide said coplanar lower flat surfaces and said coplanar upper flat surfaces transverse to the longitudinal axis of said base, and said lateral extensions have horizontal flat bottom surface portions facing said front and rear grid members; and gussets extending upwardly from said two transverse grid members at the central transverse vertical plane of said base and extending from the front and rear plates towards the central longitudinal vertical plane of said base; said coplanar vertical flat surface portions of said end portions of said mounting member of said primary lever face in the direction that said lever arms of that lever extend; said coplanar vertical fiat surface portions of said end portions of said mounting member of said secondary lever face in the direction that said lever arms of that lever extend; said mounting members of said levers between their end portions have lengths less that the distance between said upstanding vertical plates of said base with said pairs of lever arms adjacent and spaced from said plates of said base and with said end portions below said lateral extensions with said vertical flat surface portions of said end portions being below said flat surfaces of said lateral extensions for each of said levers; each of said pairs of flexure plates has a pair of holes on each side of and spaced from the flexure axis and spaced equally from the central transverse axis of the flexure plate; each of said lateral extensions of said plates and each of said end members has at said vertical flat surfaces a pair of threaded holes in horizontal alignment and spaced equally with the spacing of either pair of holes of said flexure plates; and said means pivotally mounting said primary lever and said means pivotally mounting said secondary lever including, in addition to said pairs of flexure plates, screws passing through said pairs of holes of said flexure plates and in said threaded holes in said end portions of said levers and in said lateral extensions of said upstanding plates of said base. 9. The scale of claim 8 wherein: said end portions of said levers below said lower and upper lateral extensions of said upstanding vertical plate of said base have end surfaces that are vertical, flat and normal to the longitudinal axes of the mounting members of said levers; said lateral extensions of said front upstanding vertical plates of said base have coplanar vertical flat front surfaces at their thickened distal end portions parallel to the longitudinal axis of said base; said front grid member has at its central portion a forwardly extending boss having a vertical flat surface that is coplanar with said coplanar vertical flat front surfaces of said lateral extensions of said front upstanding vertical plate of said boss; each of said flexure plates has two additional holes,

the center of each additional hole being in alignment with and equally spaced from the centers of one of said pair of holes through which said mounting screws extend, each of said lateral extensions and said end portions of said levers has a similarly disposed additional hole, whereby during assembly of said scale each lever can be supported on said upstanding vertical plates by mounting pins with the mounting screws loosely positioned until the lever is aligned with said vertical surface at the end of the lever coplanar with said vertical flat surfaces of said thickened portions of said lateral extensions of said front upstanding plate and of the forwardly extending boss of said front grid member;

said lever arm of said primary lever that is adjacent said front grid member has upstanding bosses at its proximal portion and adjacent its distal portion, said bosses having coplanar top flat horizontal surfaces;

said lever arm of said secondary lever that is adjacent said front grid member has upstanding bosses at its proximal portion and adjacent its distal portion, said bosses having coplanar top fiat horizontal surfaces;

said front grid member has bosses on its top surface at vertical transverse planes passing through said bosses on said levers, said bosses of said front grid member having coplanar flat horizontal surfaces; and

said main portion of said base having on said front and rear grid members downwardly extending bosses having coplanar flat horizontal downwardly facing surfaces.

10. The scale of claim 9 wherein:

said intermediate extension of said mounting member of said secondary lever comprises a pair of spaced plate extensions having parallel facing surfaces and coplanar horizontal flat top surface portions;

said means fixedly engaging said ferrule rod of said cable assembly connecting said intermediate arm of said primary lever and said extension of said secondary lever comprises:

a bracket having at its upper portion lateral extensions fixedly mounted on said coplanar flat top surface portions of said plate extensions and having at its vertical surface facing away from said secondary lever a central recess conforming to one-half of a countersunk hole;

a cable clamp member having at its upper portion lateral extensions mounted on said top surface portions of said plate extensions. having a vertical surface that faces said recessed surface of said bracket and that is flat except for a complementary recess that provides the balance of a countersunk hole when said bracket and said clamp member are secured together. the bottom portion of the countersunk hole thus provided having a smaller diameter than the flexible cable to secure said cable between said bracket and said clamp;

screws securely mounting said clamp member on said bracket;

a cable hanger mounted on said bracket and said clamp member, said hanger having a vertical hole in alignment with the countersunk hole provided by said bracket and said clamp member and having horizontal threaded holes to said vertical hole;

screws securing said hanger on said bracket;

a bushing having a threaded vertical central hole, a lower portion with a cylindrical configuration and an intermediate annular recess, and an upper portion of larger diameter resting on said hanger, said lower portion of said bushing mounted in said vertical hole of said hanger and the threaded end portion of said ferrule rod of said cable assembly connected to said intermediate arm in said threaded vertical hole of said bushing; and

screws in said horizontal holes in said cable hanger securing said bushing by engaging said annular recess of said bushing.

11. The scale of claim 10 wherein said platform has a unitary grid construction for its main horizontal portion comprising front and rear grid members, end grid members and intermediate transverse and longitudinal grid members, said end grid members having a length so that said front and rear grid members are generally in vertical alignment with said front and rear vertical plates of said base, said front and rear grid members of said platform having a recessed construction at their central portion in which recesses said upstanding vertical plates of said base are disposed, and said grid construction of said main portion of said platform having on its front and rear grid members upstanding bosses with coplanar flat horizontal top surfaces, said scale further including a platform cover sheet having a flat main portion resting on said upstanding bosses of said platform.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,894 ,595

DATED July 15 1975 INVENTOR(S) 1 Column Column Column Column Column [SEAL] Chester S. Czyryk It IS certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

"having" should read --facing-. I "at their" should read of their.

"each" should read end-. "on" should read in-.

"and" should read --that. "low" should read load-.

"adjacent that" should read -adjacent--. "side end. portions" should read said end portions.

"hole" should read -holes.

Engncd and Scaled this thirtieth Day of September 1975 4, Line 24, 5, Line 24, Line 50,

11, Line 15, Line 24,

17 Line 14, Line 14, Line 44,

20, Line 1,

Arresr:

RUTH C. MASON Allvslmg ()jflrer 

1. A platform scale comprising: a horizontal base; a primary U-shaped lever having in a unitary construction an elongated mounting member, a pair of lever arms extending horizontally from the same side of said mounting member adjacent its ends, and an intermediate arm extending horizontally from said mounting member in a direction that is normal to the longitudinal axis of said mounting member and from the side of said mounting member that is opposite to the side from which said pair of lever arms extend; a secondary U-shaped lever having in a unitary construction an elongated mounting member and a pair of lever arms extending horizontally from the same side of said mounting member adjacent its ends, said mounting member having an intermediate portion extending horizontally and normal to the longitudinal axis from the side of said mounting member that is opposite to the side from which said pair of lever arms of said secondary lever extend; means connected to said base and to said mounting member of said primary lever to pivotally mount that mounting member at a horizontal axis that is at a lower elevation above the central transverse portion of said base, with the longitudinal axis of that mounting member at a vertical plane transverse to the longitudinal axis of said base and with the distal end portions of said pair of lever arms of said primary lever above the front and rear corner portions of one end of said base; means connected to said base and to said mounting member of said secondary lever to pivotally mount that mounting member at a horizontal axis that is at an upper elevation above the central transverse portion of said base, with the longitudinal axis of that mounting member at a vertical plane transverse to the longitudinal axis of said base and passing through said intermediate arm of said primary lever, with the said extension of said intermediate portion of said mounting member of said secondary lever directly above said intermediate arm of said primary lever, and with the distal end portions of said pair of lever arms of said secondary lever above the front and rear corner portions of the other end of said base; a horizontal platform; force-transmitting support means connected to the corner portions of said platform and to the distal end portions of said pairs of lever arms of said levers to support said platform above said lever arms; force-transmitting means connected to said intermediate extension of said mounting arm of said secondary lever and to said intermediate arm of said primary lever; low cell means mounted on said base adjacent that its said other end and below the distal end portion of said intermediate arm of said primary lever; and force-transmitting means connected to said distal end portion of said intermediate arm and to said load cell means to provide a stress in said load cell means when said intermediate arm is raised.
 2. A platform scale comprising: a horizontal base having front and rear upstanding portions at the central part of the front and rear margins of said base, each upstanding portion providing a vertical mounting post having at an upper elevation a vertical flat surface facing one end of said scale and at a lower elevation a vertical flat surface facing one end of said scale, said upper flat surfaces of said upstanding portions being at one vertical plane transverse to the longitudinal axis of said base and said lower flat surfaces being at another vertical plane transverse to the longitudinal axis of said base; a primary U-shaped lever having in a unitary construction an elongated mounting member, a pair of lever arms spaced from each other and extending horizontally from the same side of said mounting member adjacent its end portions, and an intermediate arm extending horizontally from said moUnting member in a direction that is normal to the longitudinal axis of said mounting member and from the side of said mounting member that is opposite to the side from which said pair of lever arms extend, side end portions of said mounting member extending axially beyond said pair of lever arms and having coplanar vertical flat surface portions on the same side of the longitudinal axis of said mounting member; a secondary U-shaped lever having in a unitary construction an elongated mounting member and a pair of lever arms spaced from each other and extending horizontally from the same side of said mounting member adjacent its end portions, said mounting member having an intermediate portion extending horizontally and normal to the longitudinal axis of said mounting member from the side of said mounting member that is opposite to the side from which said pair of lever arms of said secondary lever extend and said end portions of said mounting member extending axially beyond said pair of lever arms and having coplanr vertical flat surface portions on the same side of the longitudinal axis of said mounting member; means, including a first pair of flexure plates, pivotally mounting said primary lever on said upstanding portions of said base with said pair of lever arms of said primary lever extending to positions above front and rear corner portions of one end of said base, said mounting means connecting said primary lever at its said coplanar vertical flat surface portions to one of the upper and lower horizontal marginal portions of said first pair of flexure plates and connecting said upstanding portions at their said lower vertical flat surfaces to said first pair of flexure plates at the other of said upper and lower marginal portions of said first pair of flexure plates to provide a common horizontal flexure axis transverse to the longitudinal axis of said base and to provide the end portions of said mounting member of said primary lever vertically spaced from said upstanding portions at their said lower vertical flat surfaces; means, including a second pair of flexure plates, pivotally mounting said secondary lever on said first and second upstanding portions of said base with said pair of lever arms of said secondary lever extending to positions above front and rear corner portions of the other end of said base, said mounting means connecting said secondary lever at its said coplanar vertical flat surface portions to one of the upper and lower horizontal marginal portions of said second pair of flexure plates and connecting said first and second upstanding portions at their said upper vertical flat surfaces to said second pair of flexure plates at the other of said upper and lower marginal portions of said second pair of flexure plates to provide a common horizontal flexure axis transverse to the longitudinal axis of said base and to provide the end portions of said mounting member of said secondary lever vertically spaced from said upstanding portions at their said upper vertical flat surfaces; a platform having a main horizontal portion, with the longitudinal axis parallel to the longitudinal axis of said base and with corner portions above the corner portions of said base, a first pair of downwardly extending legs at the front and rear corner portions of one end of the main portion of said platform below which are located the front and rear corner portions of said one end of said base, a first pair of horizontal feet extending from said first pair of legs to a position below the distal end portions of said lever arms of said primary lever, a second pair of downwardly extending shorter legs at the front and rear corner portions at the other end of the main portion of said platform below which are located the front and rear corner portions of said other end of said base, a second pair of horizontal feet extending from said second pair of legs to a position below the distal end portions of said lever arms of said secondary lever; means connected to tHe distal end portions of said lever arms of said primary lever and to said first pair of feet to provide a part of the support of said platform by said lever arms; means connected to the distal end portions of said lever arms of said secondary lever and to said second pair of feet to provide the other part of the support of said platform by said lever arms; means connected to said intermediate extension of said mounting member of said secondary lever and to said intermediate arm of said primary lever at a location spaced from the distal end portion of said intermediate arm and spaced from said mounting member of said primary lever, said intermediate extension of said mounting member of said secondary lever and said intermediate arm of said primary lever being located on said levers so that said extension is directly above said intermediate arm; load cell means mounted on said base adjacent its said other end and below the distal end portion of said intermediate arm of said primary lever; and means connected to said distal end portion of said intermediate arm and to said load cell means to provide a stress in said load cell means when said intermediate arm is raised.
 3. The scale of claim 2 wherein: said pairs of lever arms of said levers extend normal to the longitudinal axes of the corresponding mounting member of said levers and each lever arm of said primary lever has its longitudinal axis in alignment with that of one of said lever arms of said secondary lever; each of said distal end portions of said pairs of lever arms has a vertical countersunk hole at the longitudinal axis of that lever arm and horizontal threaded holes to the larger diameter portion of the countersunk hole; each of said pairs of feet has a threaded vertical hole located below said countersunk hole in the distal end portion of the lever arm connected to that foot; said means connecting said distal end portions of said lever arms of said primary lever to said first pair of feet and said means connecting said distal end portions of said lever arms of said secondary lever to said second pair of feet comprises: four flexible cable assemblies, each assembly including: a vertical flexible cable; a ferrule rod having a threaded cylindrical bottom portion threaded into said hole in one of said feet and an upper portion with a central vertical hole in which the bottom end portion of said flexible cable is secured; and a ferrule with a stepped cylindrical surface mounted on one of said lever arms in the countersunk hole and having a central vertical hole, in which one end portion of said flexible cable is secured in the portion of smaller diameter and having an intermediate annular recess in the cylindrical surface of larger diameter portion; and screws mounted in said horizontal threaded holes in said distal end portion of the lever arm and engaging said stepped ferrule at its said intermediate annular recess; and said intermediate arm of said primary lever having an inverted countersunk hole below said intermediate extension of said mounting member of said secondary lever and horizontal threaded holes to the large diameter portion of that countersunk hole; said means connecting said intermediate extension and said intermediate arm of said primary lever comprising: another of said flexible cable assemblies in an inverted position with said stepped ferrule being mounted in said inverted countersunk hole of said intermediate arm and with the ferrule rod at the elevation of said extension of said mounting member of said secondary lever; screws mounted in said horizontal threaded hole in said intermediate arm and engaging said stepped ferrule at its said intermediate annular recess; and means mounted on that intermediate extension of said secondary lever and fixedly engaging that ferrule rod; said intermediate arm of said primary lever has at its distal portion a vertical countersunk hole and horizontal threaded holEs to the larger diameter of that countersunk hole; and said means connecting said distal end portion of said intermediate arm comprises: another of said flexible cable assemblies having its ferrule rod threadedly engaging said load cell means and having its stepped ferrule in said countersunk hole; and screws mounted in said horizontal threaded holes in said distal end portion of said intermediate arm and engaging said stepped ferrule at its said intermediate annular recess.
 4. The scale of claim 3 wherein: said intermediate extension of said mounting member of said secondary lever comprises a pair of spaced plate extensions having parallel facing surfaces and coplanar horizontal flat top surface portions; said means fixedly engaging said ferrule rod of said cable assembly connecting said intermediate arm of said primary lever and said extension of said secondary lever comprises: a bracket having at its upper portion lateral extensions fixedly mounted on said coplanar flat top surface portions of said plate extensions and having at its vertical surface facing away from said secondary lever a central recess conforming to one-half of a countersunk hole; a cable clamp member having at its upper portion lateral extensions mounted on said top surface portions of said plate extensions, having a vertical surface that faces said recessed surface of said bracket and that is flat except for a complementary recess that provides the balance of a countersunk hole when said bracket and said clamp member are secured together, the bottom portion of the countersunk hole thus provided having a smaller diameter than the flexible cable to secure said cable between said bracket and said clamp; screws securely mounting said clamp member on said bracket; a cable hanger mounted on said bracket and said clamp member, said hanger having a vertical hole in alignment with the countersunk hole provided by said bracket and said clamp member and having horizontal threaded holes to said vertical hole; screws securing said hanger on said bracket; a bushing having a threaded vertical central hole, a lower portion with a cylindrical configuration and an intermediate annular recess, and an upper portion of larger diameter resting on said hanger, said lower portion of said bushing mounted in said vertical hole of said hanger and the threaded end portion of said ferrule rod of said cable assembly connected to said intermediate arm in said threaded vertical hole of said bushing; and screws in said horizontal holes in said cable hanger securing said bushing by engaging said annular recess of said bushing.
 5. The scale of claim 4 wherein said mounting for one of said cable assemblies on the distal portions of said lever arms of said primary lever and for one of said cable assemblies on the distal end portions of said lever arms of said secondary lever is provided for each by: a cylindrical mounting member having: an annular recess in its bottom surface portion; an eccentric vertical countersunk hole in which is located the stepped ferrule of the cable assembly with the larger diameter portion of the ferrule in the countersunk portion of the hole in said cylindrical mounting member; and horizontal threaded holes in its upper portion to said countersunk hole; and screws in said threaded holes engaging the annular recess in the stepped ferrule, said screws in said lever arm engaging the annular recess in said cylindrical eccentric mounting member.
 6. The scale of claim 5 wherein said eccentric mounting members in the countersunk holes of said lever arms are in the lever arms that are adjacent the front of said base.
 7. The scale of claim 6 wherein: said lower flat surfaces of said upstanding portions of said base face in the direction that said lever arms of said primary lever extend; said upper flat surfaces of said upstanding portions of said base face in the direction that said arms of said secondarY lever extend; said coplanar vertical flat surface portions of said end portions of said mounting member of said primary lever face in the direction that said lever arms of that lever extend; and said coplanar vertical flat surface portions of said end portions of said mounting member of said secondary lever face in the direction that said lever arms of that lever extend.
 8. The scale of claim 3 wherein: said horizontal base having in a unitary construction: a main horizontal portion with a grid construction comprising: front and rear grid members; first and second end grid members constituting said one and said other ends of said base; and transverse and longitudinal grid members within the area defined by said front and rear and said end members to provide with them the grid construction having open spaces at the four corner portions of said main horizontal portion and having a central open space from which two of said transverse grid members extend to the front and rear grid members at the central vertical plane of said horizontal main portion; front and rear vertical plates extending upwardly from the central portion of said front and rear grid members, respectively, and constituting said upstanding portions of said base, each of said vertical plates having a lower lateral extension, toward the transverse vertical plane containing said first end grid member, and an upper lateral extension, toward the transverse vertical plane containing said second end grid member, with the distal end portions of said upper and lower lateral extensions of said plates being thickened to provide sufficient horizontal width at the end surface for mounting of said pairs of flexure plates on said four lateral extensions, and with the end surfaces of these thickened portions of said lateral extensions being vertical and flat to provide said coplanar lower flat surfaces and said coplanar upper flat surfaces transverse to the longitudinal axis of said base, and said lateral extensions have horizontal flat bottom surface portions facing said front and rear grid members; and gussets extending upwardly from said two transverse grid members at the central transverse vertical plane of said base and extending from the front and rear plates towards the central longitudinal vertical plane of said base; said coplanar vertical flat surface portions of said end portions of said mounting member of said primary lever face in the direction that said lever arms of that lever extend; said coplanar vertical flat surface portions of said end portions of said mounting member of said secondary lever face in the direction that said lever arms of that lever extend; said mounting members of said levers between their end portions have lengths less that the distance between said upstanding vertical plates of said base with said pairs of lever arms adjacent and spaced from said plates of said base and with said end portions below said lateral extensions with said vertical flat surface portions of said end portions being below said flat surfaces of said lateral extensions for each of said levers; each of said pairs of flexure plates has a pair of holes on each side of and spaced from the flexure axis and spaced equally from the central transverse axis of the flexure plate; each of said lateral extensions of said plates and each of said end members has at said vertical flat surfaces a pair of threaded holes in horizontal alignment and spaced equally with the spacing of either pair of holes of said flexure plates; and said means pivotally mounting said primary lever and said means pivotally mounting said secondary lever including, in addition to said pairs of flexure plates, screws passing through said pairs of holes of said flexure plates and in said threaded holes in said end portions of said levers and in said lateral extensions of said upstanding plates of said base.
 9. The scale of claim 8 wherein: said end portions of said levers beLow said lower and upper lateral extensions of said upstanding vertical plate of said base have end surfaces that are vertical, flat and normal to the longitudinal axes of the mounting members of said levers; said lateral extensions of said front upstanding vertical plates of said base have coplanar vertical flat front surfaces at their thickened distal end portions parallel to the longitudinal axis of said base; said front grid member has at its central portion a forwardly extending boss having a vertical flat surface that is coplanar with said coplanar vertical flat front surfaces of said lateral extensions of said front upstanding vertical plate of said boss; each of said flexure plates has two additional holes, the center of each additional hole being in alignment with and equally spaced from the centers of one of said pair of holes through which said mounting screws extend, each of said lateral extensions and said end portions of said levers has a similarly disposed additional hole, whereby during assembly of said scale each lever can be supported on said upstanding vertical plates by mounting pins with the mounting screws loosely positioned until the lever is aligned with said vertical surface at the end of the lever coplanar with said vertical flat surfaces of said thickened portions of said lateral extensions of said front upstanding plate and of the forwardly extending boss of said front grid member; said lever arm of said primary lever that is adjacent said front grid member has upstanding bosses at its proximal portion and adjacent its distal portion, said bosses having coplanar top flat horizontal surfaces; said lever arm of said secondary lever that is adjacent said front grid member has upstanding bosses at its proximal portion and adjacent its distal portion, said bosses having coplanar top flat horizontal surfaces; said front grid member has bosses on its top surface at vertical transverse planes passing through said bosses on said levers, said bosses of said front grid member having coplanar flat horizontal surfaces; and said main portion of said base having on said front and rear grid members downwardly extending bosses having coplanar flat horizontal downwardly facing surfaces.
 10. The scale of claim 9 wherein: said intermediate extension of said mounting member of said secondary lever comprises a pair of spaced plate extensions having parallel facing surfaces and coplanar horizontal flat top surface portions; said means fixedly engaging said ferrule rod of said cable assembly connecting said intermediate arm of said primary lever and said extension of said secondary lever comprises: a bracket having at its upper portion lateral extensions fixedly mounted on said coplanar flat top surface portions of said plate extensions and having at its vertical surface facing away from said secondary lever a central recess conforming to one-half of a countersunk hole; a cable clamp member having at its upper portion lateral extensions mounted on said top surface portions of said plate extensions, having a vertical surface that faces said recessed surface of said bracket and that is flat except for a complementary recess that provides the balance of a countersunk hole when said bracket and said clamp member are secured together, the bottom portion of the countersunk hole thus provided having a smaller diameter than the flexible cable to secure said cable between said bracket and said clamp; screws securely mounting said clamp member on said bracket; a cable hanger mounted on said bracket and said clamp member, said hanger having a vertical hole in alignment with the countersunk hole provided by said bracket and said clamp member and having horizontal threaded holes to said vertical hole; screws securing said hanger on said bracket; a bushing having a threaded vertical central hole, a lower portion with a cylindrical configuration and an intermediate annular recess, and an upper portion of larger diamEter resting on said hanger, said lower portion of said bushing mounted in said vertical hole of said hanger and the threaded end portion of said ferrule rod of said cable assembly connected to said intermediate arm in said threaded vertical hole of said bushing; and screws in said horizontal holes in said cable hanger securing said bushing by engaging said annular recess of said bushing.
 11. The scale of claim 10 wherein said platform has a unitary grid construction for its main horizontal portion comprising front and rear grid members, end grid members and intermediate transverse and longitudinal grid members, said end grid members having a length so that said front and rear grid members are generally in vertical alignment with said front and rear vertical plates of said base, said front and rear grid members of said platform having a recessed construction at their central portion in which recesses said upstanding vertical plates of said base are disposed, and said grid construction of said main portion of said platform having on its front and rear grid members upstanding bosses with coplanar flat horizontal top surfaces, said scale further including a platform cover sheet having a flat main portion resting on said upstanding bosses of said platform. 